+ Dr. Neal Watkins + Jackie Schryer
		An Overview of Low-temperature Oxidation Catalyst Research at the NASA Langley Research Center + Download

Low Temperature Oxidation Catalyst

Noble-metal/reducible-oxide (NMRO) catalysts were developed at the NASA Langley Research Center originally for use in long-life CO2 (carbon dioxide) lasers for space-based applications. Upon lasing, CO2 dissociates to CO (carbon monoxide) and O2 (oxygen). This dissociation results in rapid power loss and eventual complete failure of the laser. A catalyst is required to continually regenerate the CO2. The catalyst developed a Langley exhibits high activity for reaction of stoichiometric CO-O2 mixtures at low temperatures (LTOC). When it was later discovered that activity of these catalysts was enhanced when excess O2 was present, it was proposed that the catalyst might be useful for air purification. Furthermore, mechanistic considerations indicated that these and/or related catalysts could oxidize other gaseous species in addition to CO. Research to extend these catalysts to volatile organic compounds for air purification and pollution control was conducted.

Applications:

Automotive Catalytic Converters
Langley Researchers were approached by industry to replace the catalytic converter in the exhaust system of automobile to remove CO, hydrocarbons, and NOx.  NOx is a term used to designate any or all forms of nitrogen-oxygen containing gases, such as NO, N₂O, or NO₂.  Successfully adapting the catalyst for use in an automotive application involved depositing the catalytic material onto a cordierite substrate and modifying it to function at elevated temperatures for an extended time.  An automotive catalytic converter using LTOC technology has met initial EPA requirements and California emission standards for the automotive after-market. The LTOC catalytic converter does not require a warm-up period to function and uses significantly less precious metals than current commercial products, which reduces the overall cost of the converter.  The catalyst has been further modified for potential use in diesel engine applications. 

Cabin Air Purification for Racecars or Spacecraft
Extremely high levels of CO can be found in automotive cabin air in racing cars.  CO irreversibly binds to the hemoglobin found in blood reducing the oxygen transported to tissue and vital body organs. 

Smokestack Formaldehyde Remediation
More recently, Automated Control Technologies requested the development of a catalyst suitable for use for formaldehyde remediation.  Laboratory prototypes were formulated and successfully tested. 

Removal of Carbon Monoxide from Cigarette Streams
Mainstream cigarette smoke contains carbon monoxide resulting from incomplete combustion during smoking.  The tobacco industry is working to reduce the CO levels in cigarette smoke.  The LaRC catalyst may be suitable for addition to the cigarette cavity where it will oxide CO to CO₂. 

Selected Publications

1. A.N. Watkins, “An Overview of Low-temperature Oxidation Catalyst Research at the NASA Langley Research Center,” this is a white paper providing additional information as well as a full biography of papers detailing the LTOC.